Abstract

Invasive wetland plants are the primary targets of wetland management to promote native communities and wildlife habitat, but little is known about how commonly implemented restoration techniques influence nutrient cycling. We tested how experimental mowing, herbicide application, and biomass harvest (i.e., removal of aboveground biomass) treatments of Typha-invaded mesocosms altered porewater nutrient (NO3−, NH4+, PO4−3) concentration and supply rate, vegetation response, and light penetration to the soil surface. We found that while herbicide application eliminated the target species, it also reduced native plant density and biomass, as well as increased porewater nutrient concentration (PO4−3, NO3−) and supply rates (N, P, K) up to a year after treatments were implemented. Because herbicide application promotes nutrient enrichment, it may increase the likelihood of reinvasion by problematic wetland invaders, as well as cause eutrophication and deleterious algal blooms in adjacent aquatic systems. Our data suggest that biomass harvest should be considered by managers aiming to reduce Typha abundance without eradicating native diversity, avoid nutrient leaching, as well as possibly utilizing biomass for bioenergy.

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Acknowledgments

Many thanks to Jennifer Croskrey and Margaret Workman for assistance with nutrient analysis, and to Jesse Albert, Drew Monks, Erica Marcos, Nia Hurst, Kelsey Berke, and Brendan Carson for watering the mesocosms and assisting with data collection.

Funding

A portion of this project was supported by NSF (AGS-1262634) to Dave Karowe and Mary Anne Carroll, which provided Y. Rodriguez with an REU opportunity during the 2013 summer. Additionally, an EPA GLRI (GL-00E00545) award provided summer salary to B. Lawrence.

Compliance with ethical standards

Conflict of Interest

Lawrence has received research grants from the NSF and EPA. Lishawa has received research grants from the EPA and the Northern Trust Company Charitable Trust. Tuchman has received research grants from the EPA, USDA, DOE, NSF, NOAA, and the Northern Trust Company Charitable Trust. Tuchman is the director of The Institute of Environmental Sustainability (Loyola University Chicago), a member of the board of trustees for the Peggy Notebaert Nature Museum and the Delta Institute, and on the Environmental Law and Policy Center’s advisory board.